To login to LiteBlue USPS, first, ensure you have your Employee ID and USPS Self Service Password ready. Navigate to the LiteBlue login page on the USPS website. Enter your Employee ID in the "Employee ID" field and your USPS Self Service Password in the corresponding field. Click on the "Log On" button to access your LiteBlue account. Ensure you're using a secure connection and keep your login credentials confidential. Once logged in, you can access various USPS employee services, such as HR information, payroll details, work schedule, and more, making Liteblue app a vital tool for USPS employees.